


Venting Their Frustrations

by eeyore9990



Series: December Gift Fic Spree [30]
Category: Teen Wolf (TV)
Genre: Brother/Sister Incest, Dirty Talk, F/M, Incest, Lins/Derek/Stiles, M/M, Multi, Seduction, Sibling Incest, Stuart is a girl named Lins, Twincest, stilinskicest
Language: English
Status: Completed
Published: 2014-12-31
Updated: 2014-12-31
Packaged: 2018-03-04 11:19:49
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,539
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3065933
Author URL: https://archiveofourown.org/users/eeyore9990/pseuds/eeyore9990
Summary: <blockquote class="userstuff">
              <p>Derek comes home to meet his new family on the day of his mother’s wedding.  While staying in his new step-dad’s house, he over hears a blood-stirring conversation between his new step-siblings. </p><p>*check tags for warnings*</p>
            </blockquote>





	Venting Their Frustrations

**Author's Note:**

> December Fic Spree, Day 30: Gift for Anonymous!
> 
> Happy December 30!

"God, Stiles, I want to hold him down and ride his face."

Derek blinks his eyes open, eyebrows shooting up so fast the left one cramps, sending pain sizzling across his forehead. 

"I wondered why you were being so quiet. Dad did too. Thought maybe you weren’t as happy about him and Talia getting married as you said." This voice is deeper, definitely male in comparison to the husky femininity of the first speaker. 

Derek can see them in his mind’s eye: Stiles, all lanky dorkiness with his buzz cut and plaid shirts and Lins with her waist length curls and compact curves. The twin children — well, not really _children_ since they’re apparently eighteen now — of his mother’s new husband. His… _step siblings_. And apparently they’ve lived in this house for their entire lives without knowing that the vent in the bedroom they grew up in carries even the quietest whisper directly to the guest bedroom beside it.

"What?" Lins murmurs, sounding surprised. "No, idiot. Of course not. I fucking love Talia. I was just afraid if I opened my mouth, I’d end up saying something like, ‘Derek, dear, do you mind letting me choke on your cock?’" 

Derek’s mouth drops open and his dick twitches in his boxers. He tries not to imagine those bright eyes with their long, thick lashes staring up at him, or that cupid’s bow mouth stretched wide around his dick. He mostly fails. 

Stiles’ muffled laughter, which had started as soon as those words were out of Lins’ mouth, cuts off abruptly with a whomping sound. Derek tilts his head, decides it’s a pillow impacting Stiles’ face, and goes back to inadvertently eavesdropping on the twins. 

"What are you laughing about, brother mine? Like you weren’t drooling over his ass."

"Lins," Stiles moans, making Derek’s breath catch at the sound of it, "I could literally _feel_ his asshole clenching up around my tongue.”

Okay, that’s it. Derek sits up in bed, trying not to move too abruptly because he doesn’t want the bedsprings to creak and give him away. But he also can’t just lay here, listening to those two talk like that without… without. He stares down at his lap in the dark, can just make out the way his dick is tenting the material of the sheet. 

"You want to feel something clenching around your tongue, bro?" Lins’ voice is all sweetness, but Derek can _hear_ the filth that lays behind it. He can’t imagine that they’re about to do what his overactive imagination is already picturing, but…

"Fuck yeah, Lins," Stiles’ murmur is low and dirty and there’s the shifting of bed springs before a high moan breaks through the vent.

Derek’s out of the bed before he even knows he’s moved. He goes to the door of his room and stands there for a minute, just debating, but there’s a slick sucking sound wafting from the vent, and he can’t _not_ see what’s making it. Opening the door carefully, making sure it doesn’t make any noise to give him away, he creeps on tiptoe into the hall and then debates for a second over what he’s about to do. But he decides he really fucking wants to see what the twins are getting up to in their childhood beds, so he opens their bedroom door. The hinges creak, making his heart stop before picking up double-time, but when no one shouts, he steps inside and looks around. 

His eyes had been adjusted to the dark in his own room, so the light that floods through the window of this one from the streetlamp outside is more than enough for him to see Lins on her back, her hair spilling off the side of her bed, two of her own fingers shoved deep in her mouth as Stiles licks and slurps at her pussy. 

Derek has to brace himself against the wall so as to not fall over. This is some Game of Thrones shit right here. Do _all_ twins have casual sex with each other?

"Stiles," Lins slurs around her fingers, and Derek can see how shiny her lips are with spit. But then she’s pulling her hand free and pushing at Stiles’ head until he raises up, mouth still open and tongue flickering over his slick lips. Lins shoves her fingers deep inside herself and sighs, hips rocking into the motion. "You need to grow some scruff."

"Uh, yeah no. Remember no shave November last year? I looked like a meth addict."

"Ugh. I want his big hands splitting my thighs open so he can just rub his chin all over them. Scrape me up on that fucking ridiculous beard of his." Lins whines and pulls her fingers free, popping them back in her mouth and nudging her brother with her foot until he drops back between her thighs. 

Derek’s mouth goes dry and he’s taking another step before he realizes it. Wants to pull those fingers from Lins’ mouth and suck on them himself. Wants to push Stiles out of the way and taste her directly from the source.

"I wanna see if that fucking bulge is all show," Stiles says, then traces his tongue over his sister. "Not sure if I want to fuck him more or sit on his dick more."

Derek has to grab his dick and squeeze the base _hard_ , because he’s pretty sure he knows which of those he wants most. Maybe. The idea of shoving back onto Stiles’ dick isn’t exactly unwelcome either, though.

Shit, now _he’s_ torn.

"I’d like to see that. Like to see you hanging off his dick. Him hanging off yours. I bet he’s loud once you get him going. He was so quiet and polite at dinner, but I bet he’s fucking filthy in bed. Or maybe he’s a creep who gets off on watching. Bet he’d just stand there, watch it all, dick in his hand like there’s nothing better for him to do with it."

Derek’s so busy trying to stave off his own orgasm while watching Stiles dig his mouth into his sister’s cunt that it takes him a second to realize those words are a little too pointed. Eyes flaring in alarm, his gaze skips up the bed to Lins, who’s looking back at him with one eyebrow arched in judgement.

Stiles obviously senses a change in the room because he lifts his head, looks up at Lins, then follows her gaze to Derek… and smirks. “Wondered how long it’d take you,” he says. “That fucking vent is ridiculous, am I right?”

Derek thinks about protesting, thinks about being embarrassed and tripping over an apology before running from the room and leaving in the middle of the night. He thinks about all that, and then decides _fuck it_. Stepping forward, he pushes Stiles out of the way and growls, “My turn.” 

"Well, halle-fucking-luiah," Lins mutters.

Derek decides he’s had enough of these two holding the reins; with one cruel swipe of his chin over her exposed cunt, he grins viciously when she arches her back and lets out a strangled yell that’s probably loud enough to wake the entire house. “Careful, Lins,” he says with a smirk. “Don’t wanna wake your Daddy.”

"Shit," Stiles says, and Derek can hear how this entire scene is affecting him.

Turning his head, Derek pins him with a look and says, “Pretty sure there’s a better use for your mouth, kid.” Waving his ass pointedly, Derek throws Lins’ legs over his shoulders and dives in. 

"Fuck," Lins wails as he digs his tongue in deep, sucking her flavor down his throat. "Oh god, fuck, yeah. Want Stiles to get you all sloppy wet with his mouth, so wet and open he can just slide right in."

Derek wants to pull away, wants to protest, but she’s going on without him, not really looking for his input. Besides which, Stiles is apparently used to following her direction; without any warning, there’s a sloppy tongue lashing over his balls and dragging up to rub, strong and sure over his rim.

"Once he’s so deep in you I can see his dick through your belly—"

That image makes Derek groan around a mouthful of her, and the vibration against his ass tells him he wasn’t the only one so affected.

"—I want you to split me open on your cock."

Yeah. Okay. That’s a good plan. He likes that plan. When she clenches down hard on his tongue, Derek decides he _really_ likes that plan.

Stiles, however, stops what he’s doing, pulling a whine from Derek in the process, to pout, “But _I_ wanted him to fuck me.”

"Jesus _Christ_ ,” Derek growls, sinking his teeth into Lins’ thigh in frustration. “My dick’s going to fall off before _anyone_ can use it at this rate. We’re doing what she said this time, because… Ladies first.” Derek flicks his tongue over Lins’ clit just to keep her in the game. “And then tomorrow when Mom and your dad leave for their honeymoon… we’ll do everything else.”

Lins and Stiles honest to god high-five each other over his head before they all get back to work. It’s gonna be a good week.


End file.
